Guard cam for knitting machines

ABSTRACT

A guard cam for use in conjunction with a stitch cam at a feed in latch needle-knitting machines, which, with the stitch cam, provides therebetween a confined path of travel for the needless in their stitch-drawing movement and which, by itself, prevents undesirable needle overthrow and provides proper paths of travel for needles moving at the tuck and welt levels. The guard cam is adjustable in a direction at right angles to the direction of adjustment of the stitch cam whereby a fixed distance may be maintained therebetween.

United States Patent 1111 3,572,056

[72] Inventor Jack Radin [56] References Cited Brooklyn, N.Y. UNITED STATES PATENTS 1 na 885,369 1,144,884 8/1915 Ames 148/16 Flled Dec-15,196? 2,823,529 2/1958 St.Pierreetal..... 66/54 1 Patented Mar-23,1971 3,076,327 2/1963 Coile 66/54 1 8 mm g g g 1411- 3,456,460 7/1969 Mishcon 66/38X i h gg application s". Primary Examiner- Ronald Feldbaum 830,186, May 16, 1969, now abandoned AWmePNatha" which is a continuation of application Ser. No. 665,929, Sept. 6, 1967, now

abandoned- ABSTRACT: A guard cam for use in conjunction with a stitch cam at a feed in latch needle-knitting machines, which, with the stitch cam, provides therebetween a confined path of travel for the needless in their stitch-drawing movement and [54] gs f g MACHINES which, by itself, prevents undesirable needle overthrow and g provides proper paths of travel for needles moving at the tuck [52] U.S. CI. 66/57 and welt levels. The guard cam is adjustable in a direction at [51] Int. Cl. D04b 9/26 right angles to the direction of adjustment of the stitch cam [50] Field of Search 66/38-59 whereby a fixed distance may be maintained therebetween.

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GUARD CAM FOR KNITTING MAC The present invention is a continuation 'of application Ser. No. 830,186 filed on May 16, 1969, now abandoned, which in turn is a continuation of application Ser. No. 665,929 filed Sept. 6, 1967, now abandoned.

The present invention relates generally to the art of knitting and more particularly to latch needle knitting machines wherein the needles are independently movable to and from stitch forming level. The invention provides a guard cam for use in conjunction with the stitch cam at each feed of a machine to control the needle movements at the welt level, at the tuck level and during their stitch forming.

In present day latch needle multifeed knitting machines, due to the large numbers of the feeds, the needle-operating cams are sharply angled to reduce the dimension of each of the feeds. Such sharply angled cams often cause some of the needles to be over thrown, eventhough they have been initially self-frictioned in their slots with the result that such overthrown needles no longer follow their proper paths of travel and thus cause imperfections in thefabric being knitted.

It is the principal object of the present invention to provide means to prevent such overthrow of the latch needles and to cause them to follow their proper paths of travel.

Other objects and advantages of the invention will become apparent from the following detailed description of a preferred embodiment thereof as shown in the accompanying drawings and as pointed out in the appended claims.

In the drawings:

FIG. 1 is a front elevational view of the cam side of one section of the circular cam ring of a multifeed circular knitting machine showing the cam arrangements at a pair of feeds of the machine including the novel guard cam of the present invention;

FIG. 2 is a plan view of the cam section of FIG. 1;

FIG; 3 is a rear elevational view, partly in section, of the upper part ofthe cam section shown in FIG. 1; 7

FIG. 4 is a vertical sectional view taken along lines 44 of FIG. 1 and including a vertical section of an adjacent needle cylinder in'the slots of which the needles are slidably mounted;

FIG. 5 is a vertical sectional view taken along lines 5-5 of FIG. 1; I

FIG. 6 is a horizontal sectional view taken along lines 6-6 of FIG. 1;

FIG. 7 i a view showing aseries of latch needles used in the needle cylinder of the present machine;

FIG. 8 is a schematic view showing the manner in which the stitch and the novel guard cams are relatively movable;

FIG. 9 is a schematic view showing the paths of travel of the common level needle butts relative to the stitch and guard cams; and

FIG. 10 is a perspective view of the guard cam of the present invention in one form thereof as used in the cylinder cam ring of a circular knitting machine.

The arc-shaped cam section of a circular cam ringof a circular knitting machine is generally L-shaped in vertical cross section with its upright portion indicated at 10 and its base portion shown at 11, the latter being provided with a space pair of apertures 12 through which screws (not shown) are adapted to extend to secure the cam section in place on the machine adjacent to the needle cylinder, shown at 13 in FIG. 41, and alongside the like neighboring cam sections. It is understood that a plurality of circularly arranged cam sections together form the circular cam ring surrounding the needle cylinder. The radius of a cam section is obviously dependent upon the diameter of the machine's needle cylinder and its circumferential extent is sufficient to encompass the minimum length required fora plurality (here shown as two) of feeds of the machine, the latter being a multifeed machine with a maximum number of feeds. In this type of machine, the needlemoving cams have relatively steep slopes in order that each of the feeds may be encompassed within a minimum of circumferential extent of the machine's cam ring. It will be noted that the steeply angled cams often cause undesirable overthrow of the needles with the result that undesirable drop stitches are fonned in the fabric.

The type of machine shown has a certain degree of needle selection resulting from the use of a plurality of separate levelraising cam raceways (here shown as three in number) in combination with needles having elongated shanks or jack extensions which are provided with one or more needle-raisingbutts at one or more of the needleraising cam raceway levels,

the needles, in addition, all having the usual upper common level butts. I

The left-hand feed shown in FIG. 1 has a knit raise cam 14 in the lower level raceway, a knit raise cam 15 in the middle level raceway and a knit raise cam 16 in the upper level raceway. The right-hand feed shown in FIG. 1 has no raise cam in the lower level raceway, has a tuck raise cam 17 in the middle level raceway and a knit raise cam 18 in the upper level raceway. A guard cam 19 spaced from and above cam 17 prevents overthrow of the needles raised to tuck level by cam 17. The bottom surface of each raise cam acts as a guard cam to prevent overthrow of needles raised by knit raise cams therebelow. Guard earns 20 are provided above knit raise cams l6 and 18 to prevent needle overthrow. The left-hand feed is provided with a vertically adjustable stitch cam 21 and associated lower guard cam'22 while the right-hand feed'is provided with a similar vertically adjustable stitch cam 23 and associated lower guard cam 24. The guard cams 22 and 24, having slightly angled top surfaces, prevent downward needle overthrow and also relieve the tension on the newly formed loops. Guard earns 25 are also provided below each of the stitch cams to prevent any undesirable radial movement of the needle shanks. Special horizontally extending guard cams 26 are provided, by the present invention, at each of the feeds a a distance above the guard cams 20 with these cams 26 being horizontally adjustable so that they may be positioned at a fixed distance from the needle-lowering slopes of the stitch cams 21 and 23 regardless of their vertically adjusted positions. The guard cams 26 act to prevent the formation of drop stitches in the fabric by the needles in addition to providing for control of the needles at welt and at tuck levels.

The needles used, shown in FIG. 7 at 27, 28 and 29, are of the latch needle type with integral elongated jacks (although associated jacks may be used in place thereof) and all have the common level butts 30 thereon. Needle 27 has a butt 31 on its shank at level or the upper raceway, needle 28 has a butt 32 on its shank at a level for the middle raceway and needle 29 has a butt 33 on its shank at a level for the lower raceway. Thus any needle with a butt 31 thereon will be raised by cams l6 and 18 of the two feeds shown in FIG. 1 as well as by cams at the upper level raceway at all of the other feeds of the machine. Similarly, needless with butts 32 thereon will be raised by earns 15 and 17 of the middle level raceways and needles with butts 33 thereon will be raised by cam 14 of the lower level raceways. The needles 29 will be raised to knit level at the left-hand feed and will not be raised at all at the right-hand feed (will remain at welt level) since there is no raise cam atthe lower level raceway of the right-hand feed. Needles 27 will be raised to knit level at both feeds by cams 16 and 18 while needles 28 will be raised to knit level ky cam 15 at the left-hand feed and will be raised to tuck level by cam 17 at the right-hand feed. By appropriately placing or not placing the tuck and the knit raise cams at each of the three raceway levels at each of the feeds and by proper arrangement of the needles with one or more appropriately positioned raise butts thereon (needles may have more than one raise butt) at one or more of the raceway levels, a variety of patterning in the fabric may be obtained by causing the needles to knit, tuck and welt. Patterns may also be obtained wherein the needles are caused to knit and welt or to knit and tuck.

The cams, with theexception of earns 20 and 26, all have vertical keyways formed in their rear sides which are placed around and are affixed to vertically extending keys, the latter in turn being set in and affixed to vertical keyways formed in the inner side of the upright portion 10 of the cam section. At each feed location there is a spaced parallel pair of vertical rectangular keyways 34 and 5 milled into the inner side 36 of the upright 10. A rectangular shaped key 37, in the lower por tion of keyway 34, is retained in fixed position therein by spaced screws 38, 38 extending through suitably placed apertures in upright and into threaded engagement with the key 37, as in FIG. 4. The key 37 extends radially inwardly above the inner surface of upright 10 and into keyways 39 formed in the rear sides of the raise cams, the latter being affixed to the keys by means of suitable countersunk screws 40 passing through suitable apertures in the cams and into threaded engagement with the key 37, as in FIG. 4. A rectangular shaped key 41, in the upper portion of keyway 35, is retained in vertically adjustable position therein by means of a screw 42 passing through a vertically extending slot 43 in upright 10 of the cam section into threaded engagement with the key 41, as in FIG. 5. A washer under he head of screw 42 and spanning slot 43 permits the key to be fixed in vertically adjusted positions when the screw 42 is tightened. The key 41 also extends radially above the inner surface 36 of upright 10 and extends into vertical keyways formed in the rear sides of cams 21 and 22 which are affixed to the key 41 by means of suitable countersunk screws 45 passing through suitable apertures in the cams and into threaded engagement with the key 41, as in FIG. 5. A rectangular shaped key 46, in the lower portion of keyway 35, is retained in fixed position therein by means of a screw 47 passing through a suitable aperture in upright 10 of the cam section into threaded engagement with the key 46, as in FIG. 5. The lower portion only of the key 46, to which cam 25 is affixed, extends radially above the inner surface 36 of upright 10 and extends into a vertical keyway formed in the rear side of the cam 25 which is secured to the key 46 by mans of a suitable countersunk screw 48 passing through a suitable aperture in the cam 25 into threaded engagement with the key 46, as in FIG. 5. They key 46 is also provided with a transversely extending hole 49 which registers with a pin 50 set in the upright 10 so as to extend into the keyway. Key 46 is further provided with an axially extending hole 51 in its upper end portion within which a spring 52 under compression is placed, the free end of the spring being in contact with and maintaining upward pressure against the lower end face of key 41. The upper free end of key 41 underlies the lower face of a serrated edged disc 53 forming a part of a vertically extending screw 54 threadedly engaged in an extending upwardly from the tp surface of upright 10 of the cam section, as in FIG. 3. Thus when screw 42 is loosened, the key 41 and afiixed earns 21 and 22, under upward pressure of spring 52, may be vertically adjusted by suitably turning screw 54, after which screw 42 is again tightened to retain the parts in adjusted position. Screw 54 may be retained in its angular positions by means of a vertically extending spring detent 55 having one end thereof suitably fastened to a block 55' on the outer face of upright 10 and having its other end in spring-urged contact with the serrated edge of the disc 53.

The fixed cams and the adjustable cams 26 are mounted within a horizontally extending circularly milled groove 56 cut into the inner side of upright 10, near its upper end, as in FIGS. 1 and 4, the groove 56 extending transversely of and through the vertical keyways 34, 35 but not being as deep as the keyways. The cams 20, L-shaped in cross section, see FIG. 4, are set in the lower part of groove 56 and are affixed to the cam section by means of a suitably disposed spaced pair of screws passing through suitable apertures in the cams and into threaded engagement with the upright 10 itself, see FIG. 1. The earns 26, somewhat T-shaped in plan view, see FIG. 6, are horizontally slidably positioned in the groove 56 between its upper portion and the cams 20, being adjustably held in lace by means of screws 57 passing through horizontal slots 58 in the upright 10, FIG. 3, and into threaded engagement with the cams 26 themselves, FIGS. 1 and 3. A washer 59, spanning slot 58, underlies the head of screw 57, so that, with screw 57 l loosened, the cams 26 may be horizontally adjusted after which the screw 57 is tightened to the position of the parts. As may be seen in FIG. 10, each guard cam 26 has a pair of spaced parallel horizontally extending surfaces 60, 61, an inclined surface 62 connecting the faces 60 and 61 at one end thereof and a pair of reversely inclined surfaces 63, 64 connecting the faces 60, 61 at its other end. Surfaces 62 and 63 are generally parallel to the needle lowering slope surface of the stitch cams, as at 65 in FIG. 8, while surface 64 is generally parallel to the needle-raising surface 66 of cam 18, FIG. 9.

Referring now .to FIG. 8 the relationship of guard cams 26 to stitch cams 21 and 23 will be described. With he stitch cams in their full line positions, the guard cams, also in full line positions, are each similarly positioned relative thereto and are spaced therefrom by a preselected distance between their surfaces 62 and 65 to permit the butts 30 of the needles to pass therebetween in proper relation to the yarn-feeding means (not shown) as the needles are lowered to stitch-forming level by the stitch cams. If cam 21 is lowered to its dotted line position, its associated cam 26 is the moved to the left, FIG. 8, to its dotted line position so that the preselected distance is still maintained between their surfaces 62 and 65. Similarly, if cam 23 is raised to its dotted line position, its associated cam 26 is moved to the right, FIG. 8. to its dotted line position so that the preselected distance is still maintained between their surfaces 62 and 65. The end 67, FIG. 10, of cam unit 26 is of predetermined length so that when it is moved into contact with the surface 65 of its stitch cam surface 65 (its normal position), FIG. 1, the surfaces 62 and 65 of these two cams have the preselected distance therebetween. Such distance provides a confined path of travel of predetermined width for the needle butts 30 to travel therein. Such confined path of travel will insure that each needle hook will take the yarn and will not miss or displace it.

Referring now to FIG. 9, he paths of travel of needle butts 30 relative to the guard cam 26 will be set forth. All the needles having been lowered to stitch-forming level by stitch cam 21 and positioned by cam 22 at welt level in which the butts travel along the path line indicated at 68, thereafter needles 27 will be raised to knit level by cam 18 acting on its butts 31, needles 28 will be raised to tuck level by cam 17 acting on their butts 32 and needles 29 will remain at the welt level since there are no raise cams to act on their butts 33. The needles 27, raised to knit level, will have their butts 30 travel upwardly along the path line 69, 70 and the downwardly along the path lines 71, 72 to welt level path line 68 under the action of stitch cam 23. The needles 28, raised to tuck level, will have their butts 30 travel upwardly along the path line 69, then horizontally along the path line 72 to welt level path line 68 under the action of stitch cam 23. It is to be noted that the path lines 68, 69, 73 and 72 of the travel of butts 30 defines a trapezoidal shaped area within which the guard cam 26 is disposed.

The path lines 68 through 73 of the needle butts 30, FIG. 9, are those which are followed when there is no undesirable upward or downward overthrow of the needles, that is, they follow their proper normal paths. However, the sharply angled needle moving cams of present day multifeed machines, which presently contain extremely large (if not the maximum) numbers of feeds for a given diameter of machine, have a tendency now and then to overthrow some of the needles despite their self-frictioning shanks. Such needle overthrowing often results in undesirable knitting being formed, such as drop stitches being made in the fabric, due to the fact that the needles re not in their normally proper relation to the yarn-feeding means so that the yarn is missed or the hook of a needle out of place will interfere with the yarn feeding to an adjacent needle hook, the yarn-feeding position, relative to the needle hooks, being particularly critical in the present day fine guage machines. The guard cam 26 eliminates the drop stitches by making certain that the needle butts 30, at least from tuck to welt level along the path line 72 always follow the same path along the face of the stitch cam. Then, should a needle be raised to knit level and then move downwardly prematurely, it cannot go lower than the tuck level of surface 60 of cam 26 at which it will still take the yarn as it will move along the path line 72. Also, as to needles not raised and whose butts 30 are intended to travel the welt path line 68, they are retained at this welt level, against accidental raising, by the underside 61 of the guard cam 26 with the slope 63 acting to lower any outof-line needles. The surface 64 of guard cam 26. will raise any out-of-line needles which are intended to be' raised to tuck level.

vWhile the present guard cam has been shown in its relation to the cylinder cams of a' circular knitting machine (rib or plain); it will be obvious that the invention is not limited thereto and may be used in relation-to the similar cams of a straight knitting machine and also in relation to the similar dial cams of a circular rib knitting machine. The present invention provides a guard cam operatively related to a stitch cam to provide a confined needle path therebetween topositively control the movementof the needles in their stitch-drawing movement regardless of the stitch cam adjustment and also protects theneedles in their tuck and welt paths of travel.

I claim: 1 1

I. In a multifeed circular knitting machine having a circular slotted needle bed, latch needles each having a butt on the shank thereof and being'individually slidable in said needle bed slots, said needles being slidable in one direction to move the same from the welt position thereof to their tuck and latch-clearing positions and being slidable in the opposite directions to move the same from said latch-clearing and tuck positions to their stitch-forming position, at least one of said feeds having needle-selecting means adapted to move selected ones of saidneedles to said latch-clearing position and having selecting mean causes ndnselected. needles to pass said feed at said welt position and wherein the disposition of said added guard cam is such that said nonseleeted needles continue to pass said feed at said welt position.

4. In a knitting machine as in claim 2 wherein said guard cam causes said butts of said'so selected needles to be positively retained in said path of travel when said so selected needles are being moved from said tuck position toward said stitch-forming position 5. in a knitting machine as in claim 2 wherein said guard cam has a face disposed in spaced opposed relation to said sfitch cam face to define a pathway therebetween along which said butts of said so selected needles travel when the latter are being moved from said tuck position toward said stitch-forming position, said opposed cam faces positively retaining said butts in said path of travel.

6. In a knitting machine as in claim 5- wherein one side of said pathway is defined by said guard cam face and the other side is defined by different portions of said stitch cam face in a stitch cam provided with a cam face to engage said butts of said so selected needles to move the same to said stitch-form ing position during which said so engaged butts are adapted to normally travel in a path alongside saidstitch cam face in engagement therewith,said stitch cam-being adjustable to vary said stitch-forming position, said engagement between said stitch cam face and said so engaged butts being such that thereby some of said so selected needles may be overthrown to prematurely move toward said stitch-forming position whereby said butts will move out of said path of travel, and the combination therewith at said feed of a guard cam operatively related to said needles thereby to preventmovement past said tuck position of such of said so selected needles as may have been so overthrown. I

2. A knitting machine as in claim, 1 wherein said needleselecting means is also adapted to', move selected ones of said their said butts with said stitch cam-face thereby preventing premature movement of such needles toward said stitch-forming position.

3. In a knitting machine as in claim 2 wherein said needle- I adjusted positions of said stitch cam. I

7. In a knitting machine as in claim 5 wherein the structural relationship between said stitch cam and said guard cam is such that the width of said pathway between their said respective cam faces is constant in adjusted positions of said stitch cam. 1

8. In a knitting machine-as in claim 5 wherein said guard cam is adjustable relative to said stitch cam whereby the desired width of said pathway between their said respective cam faces may be maintained in adjusted positions of said stitch cam.

9. In a knitting machine as in claim 1 wherein said latch needles have an additional butt on their shanks and wherein said needle selecting means acts upon said additional butts to move said selected ones of said needles to said latch-clearing positions.

10. In a knitting machine as in claim 2 wherein said latch needles have an additional butt on their shanks and wherein aid needle-selecting means acts upon said additional butts to move said selected ones of said needles to said tuck and to said latch-clearing positions. I

11. In a knitting machine as in claim 10 wherein said additional butts are disposed at a plurality of positions lengthwise of said needle shanks and wherein said needle-selecting means has a plurality of of needle-moving cams adapted to be opera- .tively related to said additional butts to act upon the same to move said needles to said tuck and to said latch-clearing positions. 

1. In a multifeed circular knitting machine having a circular slotted needle bed, latch needles each having a butt on the shank thereof and being individually slidable in said needle bed slots, said needles being slidable in one direction to move the same from the welt position thereof to their tuck and latch-clearing positions and being slidable in the opposite directions to move the same from said latch-clearing and tuck positions to their stitch-forming position, at least one of said feeds having needle-selecting means adapted to move selected ones of said needles to said latch-clearinG position and having a stitch cam provided with a cam face to engage said butts of said so selected needles to move the same to said stitch-forming position during which said so engaged butts are adapted to normally travel in a path alongside said stitch cam face in engagement therewith, said stitch cam being adjustable to vary said stitch-forming position, said engagement between said stitch cam face and said so engaged butts being such that thereby some of said so selected needles may be overthrown to prematurely move toward said stitch-forming position whereby said butts will move out of said path of travel, and the combination therewith at said feed of a guard cam operatively related to said needles thereby to prevent movement past said tuck position of such of said so selected needles as may have been so overthrown.
 2. A knitting machine as in claim 1 wherein said needle-selecting means is also adapted to move selected ones of said needles to said tuck position at said feed and wherein said guard cam prevents such of said so selected needles as are in said tuck position from being overthrown by engagement of their said butts with said stitch cam face thereby preventing premature movement of such needles toward said stitch-forming position.
 3. In a knitting machine as in claim 2 wherein said needle-selecting mean causes nonselected needles to pass said feed at said welt position and wherein the disposition of said added guard cam is such that said nonselected needles continue to pass said feed at said welt position.
 4. In a knitting machine as in claim 2 wherein said guard cam causes said butts of said so selected needles to be positively retained in said path of travel when said so selected needles are being moved from said tuck position toward said stitch-forming position.
 5. in a knitting machine as in claim 2 wherein said guard cam has a face disposed in spaced opposed relation to said stitch cam face to define a pathway therebetween along which said butts of said so selected needles travel when the latter are being moved from said tuck position toward said stitch-forming position, said opposed cam faces positively retaining said butts in said path of travel.
 6. In a knitting machine as in claim 5 wherein one side of said pathway is defined by said guard cam face and the other side is defined by different portions of said stitch cam face in adjusted positions of said stitch cam.
 7. In a knitting machine as in claim 5 wherein the structural relationship between said stitch cam and said guard cam is such that the width of said pathway between their said respective cam faces is constant in adjusted positions of said stitch cam.
 8. In a knitting machine as in claim 5 wherein said guard cam is adjustable relative to said stitch cam whereby the desired width of said pathway between their said respective cam faces may be maintained in adjusted positions of said stitch cam.
 9. In a knitting machine as in claim 1 wherein said latch needles have an additional butt on their shanks and wherein said needle selecting means acts upon said additional butts to move said selected ones of said needles to said latch-clearing positions.
 10. In a knitting machine as in claim 2 wherein said latch needles have an additional butt on their shanks and wherein aid needle-selecting means acts upon said additional butts to move said selected ones of said needles to said tuck and to said latch-clearing positions.
 11. In a knitting machine as in claim 10 wherein said additional butts are disposed at a plurality of positions lengthwise of said needle shanks and wherein said needle-selecting means has a plurality of of needle-moving cams adapted to be operatively related to said additional butts to act upon the same to move said needles to said tuck and to said latch-clearing positions. 